Design of the Solar System’s Gas Giants

August 11, 2008

By Dr. Hugh Ross

New understanding of the solar system by team of five theoreticians from three different continents has produced even more evidence for the design of the solar system’s gas giant planets (Jupiter, Saturn, Uranus, and Neptune) for the benefit of advanced life on Earth.

The masses and orbits of the solar system’s four gas giant planets are crucial for life on planet Earth. Without the gas giant planets, Earth would suffer from frequent life-destructive collision events from asteroids and comets. Additionally, a too-frequent cometary impact rate could have resulted in too much surface water for Earth.

The four gas giant planets act as gravitational shields for Earth. The more massive the planet and/or the closer the planet to Earth, the more effectively that planet will either deflect asteroids and comets away from a collision path with Earth or absorb the collisions itself. However, the gas giant planet cannot be too massive or too close to Earth. If it is, then, over time, its gravity will disturb Earth from the highly fine-tuned orbital path essential for the support of advanced life. For the same reason the gas giant planet’s orbital eccentricity (degree of ellipticity) and inclination (tilt) must be close to zero.

In order to adequately protect Earth from collision events without being gravitationally disturbed, the protection must come from not just one gas giant planet, but rather several. Previous work by certain members of the team of theoreticians, and others, shows that the mass and orbital characteristics for each of the solar system’s gas giant planets are exquisitely optimized to make the long-term survival of a wide diversity of both primitive and advanced life-forms on Earth possible. Their latest publication demonstrates exactly how these four planets attained their remarkable characteristics.

The team determined that in the presence of the gas disk about the Sun, from which all four gas giants formed, the configurations where the planets lock into a “quadruple mean-motion resonance,” are the only configurations for these planets that are able to reach a steady state (stable constant orbits) 1. That is, each planet would be making exactly one, two, three, four, etc., or one-half, one-third, one-quarter orbits for every single orbit of its neighbor. After the disappearance of the gas the team found that just two configurations, where the four planets are spread far apart from one another, allowed the planets to remain stable for more than just a few million years.

Gas giant planets exert powerful gravitational influences on other planets. Because of this, it is crucial that the gas giant planets maintain stable orbital configurations for a few billion years in order for life to be possible for more than just a short time period within the planetary system. However, over time, mean-motion resonances among the gas giant planets would destabilize the orbit of a life-friendly planet in the same system. Therefore, the team concluded that some special feature of the solar system must operate to move the four gas giant planets from their original stable configuration with a quadruple mean-motion resonance into another configuration free of mean-motion resonances among the gas giants that, nonetheless, is stable over a very long time period.

The team discovered that such an extraordinary event could occur if, after the disappearance of the gas disk, a just-right planetesimal disk (a disk made up of very large asteroids and comets) remains just beyond the orbit of the outermost gas giant planet, namely Neptune. Such a planetesimal disk would gravitationally interact with the four gas giant planets, causing the four planets to migrate outward from their stable birth configuration to the orbits they currently maintain. A bonus arising from the interaction and migration is that the orbits of the four planets would become more circular, less inclined, and, thus, much less likely to ever destabilize the orbit of Earth.

In summary, the team demonstrated that Jupiter, Saturn, Uranus, and Neptune could not have formed in their present positions without becoming unstable. They had to have formed in highly fine-tuned positions and in a highly fine-tuned configuration. However, if they had remained in that configuration, long-term life on Earth would have proved impossible.

Another highly fine-tuned solar system feature was necessary for long-term life to become possible on Earth: a planetesimal disk of the just-right distance from the Sun, of the just-right width, of the just-right mass, and of the just-right distribution of planetesimal masses and orbits. Furthermore, to avoid endangering advanced life on Earth by planetesimal encounter events and to prevent the gas giant planets from continuing to migrate outward, it was vital that at some point in the outward migration of the four planets that about 99 percent of the planetesimals be scattered out of the planetesimal disk. This scattering event would have been a relatively late occurrence in the history of the solar system and helps explain why life did not appear on Earth, at least not in any measurable quantity, until 3.8 billion years ago.

The recent work done by the internationally diverse team of theoreticians illustrates in dramatic fashion that the more astronomers learn about the solar system, the more evidence they find that reveals the handiwork of a supernatural, super-intelligent Creator.

Dr. Hugh Ross

Reasons to Believe emerged from my passion to research, develop, and proclaim the most powerful new reasons to believe in Christ as Creator, Lord, and Savior and to use those new reasons to reach people for Christ. Read more about Dr. Hugh Ross.

References:

Alessandro Morbidelli et al., “Dynamics of the Giant Planets of the Solar System in the Gaseous Protoplanetary Disk and Their Relationship to the Current Orbital Architecture,” Astronomical Journal 134 (November 2007): 1790-98.

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